I don't understand the downvotes, are managers really fine with ruining the productivity of their reports just because their own performance wouldn't be hurt in

I don't understand the downvotes, are managers really fine with ruining the productivity of their reports just because their own performance wouldn't be hurt in the same scenario? Or don't they recognize that switching to a task you have had a lot of deliberate practice doing costs a lot less than switching to a task you know you are bad at? Engineer: I would be more productive if we changed X. Manager: You are lying, I am not hurt by X, you shouldn't be either!!! Just try harder and you will be just as productive!